Bunkers, fog showers: How countries are keeping their cool

As temperatures rise, underground spaces are being repurposed, institutions are opening their doors and cooling sprays are being installed along arterial roads.

As the toll from heat waves rises — in just one year, 2003, in Europe alone, 70,000 died from a record-setting heat wave — countries are starting to explore extreme measures to get around extreme temperatures.

Vienna became one of Europe’s first cities to combat urban heat, when it introduced fog showers in 2018. (Shutterstock)

* China has begun to repurpose its World War 2-era air-raid shelters, to allow people to seek shelter during heat waves. In cities such as Hangzhou on its east coast, Wuhan at its centre, and Hebei near Beijing, these shelters have been fitted with

A home built into cooling rock, in Coober Pedy, Australia. (Shutterstock)

* In Coober Pedy, an opal-mining town in Australia where temperatures routinely reach 52 degrees Celsius in summer, an existing approach to housing could offer tips for the future.

About 60% of the population lives in homes built into the sandstone and siltstone rock, with much of the town built four metres away from the exterior of the rock. This keeps indoor temperatures at below 23 degrees C. While this works well in arid regions such as Coober Pedy, it can be problematic for areas with higher humidity levels. An example is the London Underground, where tunnels routinely grapple with black mould.

In India, meanwhile, roofs are being painted white in subsidised government projects, and startups are working on battery-operated air-conditioned helmets for outdoor workers such as traffic police personnel. But as more towns and cities breach new highs — Hamirpur in Himachal Pradesh hit 43 degrees Celsius this month; Chandigarh hit 44.5, its highest in 22 years — more needs to be done.

“We have a huge population that works out in the open. Any solution needs to be primarily focussed on this most vulnerable section,” says Udit Bhatia, assistant professor of civil engineering at IIT Gandhinagar. “One cannot approach the dry heat of Delhi and the humid heat of Kolkata the same way. Populations are dense and unevenly distributed. It is important to take these factors into consideration.”